Boring tool

ABSTRACT

In general, this invention relates to a tool for forming bores in material, wherein the tool has a shaft, a cutting element mounted on one end of the shaft, and a suction passage in the shaft to remove chips.

[ 51 Sept. 26, 1972 United States Patent Nicholas 2,971,409 2/1961Peters et a1..................408/59 665,158 1/1901Abrams.......................408/58 1,451,610 4/1923 Gestas 408/58Primary Examiner-Gerald A. Dost Attorney-Norman S. Blodgett [22] Filed:Oct. 23, 1970 [21] App1.No.: 83,462

7] ABSTRACT In general, this invention relates to a tool for formingbores in material, wherein the tool has a shaft, a

[51] Int. Cl. 29/03 Of cutting element mounted on one end of the shaftand a suction passage in the shaft to remove chips.

[56] References Cited UNITED STATES PATENTS 6 Claims, 9 Drawlng Figures754,350 3/1904 Shaull et a1. .................408/58 PATENTEDsEP2s m2SHEET 1 BF 2 GEORGE C. NICHOLAS I N V E NTOR.

P'A'TE'N'TEDsmes m2 SHEET 2 BF 2 FIG. 9

FIG. 8

BORING TOOL BACKGROUND OF THE INVENTION The efficient and accurateproduction of bores (especially deep bores) in workpieces is a matter ofno small interest in the machine tool industry. This is evidenced by thenumerous patents in this area. As far as the cutting tool itself isconcerned, the so-called boring tool has been found to be mostsatisfactory for many applications. A boring tool involves a shankmounted in the chuck of a machine tool, having at its working end acutting element of hardened material such as high-speed steel orcarbide. Several important problems have become apparent in the use ofthis type of tool on bores of any significant depth where the materialis cast iron. First, the problem of attaching the cutting element to theshank exists; if the shank must be long, it cannot be made of the hard,brittle material necessary in the cutting element. The problem withconnecting non-homogeneous materials is that normal methods, such asadhesion or welding, will not produce a bond of sufficient workingstrength. The necessary alternative is the use of various mechanicalbonds such as set-screws and rivets which, sometimes, operateeffectively to make the system workable. The drawback, however, iswell-known in the art and is one of which leads to the second problem.

In many of the more practical mechanical bonding designs, the cuttingelement must be mounted asymmetrically with respect to the shank.Cutting elements which are positioned non-symmetrically result inunbalanced force couples and, thereby, deflection of the shaft andgeneral vibration. High-speed, accurate work becomes impossible withoutguides along the length of the bore.

The last problem (and one which is particularly acute in friablematerials where boring tools would be expected to perform best) has todo with the removal of chips. As the boring tool moves through theworkpiece, the accumulated chips resist the cutting operation and scorethe walls of the bore. To be effective, the chip removal must take placeat the working face, since removal at a distance from the work facestill allows the chip to interfere with the cutting operation. Previousattempts to achieve the former effect have been, at best, limited inusefulness.

These and other difficulties experienced with the prior art devices havebeen obviated in a novel manner by the present invention.

It is, therefore, an outstanding object of the invention to provide aboring tool that removes the chips that it produces.

Another object of this invention is the provision of a boring tool whosestructure is not significantly weakened by adding a self-cleaningfunction.

A further object of the present invention is the provision of a boringtool with an attached cutting element which cuts into the workpiece andthen continues to crush the chips until they are small enough to beremoved by means of a suction bore located adjacent the cutting element.

It is another object of the instant invention to provide a boring toolwhich comprises a suction system which cleans chips out of the workpiecebut does not interfere with the operation of the boring tool.

A still further object of the invention is the provision of a boringtool which has a tungsten carbide cutting element attached symmetricallyto it so that it does not block a chip removing system.

Another object of the invention is the provision of a boring tool havinga carbide cutting element attached by means which is predominantlymechanical, thus allowing operation at high temperature.

SUMMARY OF THE INVENTION In general, the present invention consists of aboring tool having a shank which is held by the chuck of a machine toolat one end, which has a cutting element attached to the other end of theshank, which has a bore extending axially of the shaft from the cuttingelement, and which has means for applying suction to the bore.

BRIEF DESCRIPTION OF THE DRAWINGS The character of the invention,however, may be best understood by reference to one of its structuralforms, as illustrated by the accompanying drawings, in which:

FIG. 1 is an elevational view of a boring tool embodying the principlesof the present invention,

FIG. 2 is a perspective view of the working end of the boring toolshowing the end of the shank, the suction bore, and the cutting element,

FIG. 3 is a front elevational view of the working end of the boringtool,

FIG. 4 is a left elevation of the working end of the boring tool,

FIG. 5 is a bottom plan view of the working end of the boring tool,

FIG. 6 is a sectional view of FIG. 1 showing the driven end of the shankincluding a suction seal,

FIG. 7 is a partial sectional view of a modified form of the invention,

FIG. 8 is a bottom plan view of the bar shown in FIG. 7 showing theconnection between parts of the invention, and

FIG. 9 is a sectional view of the seals and bearings used in theembodiment of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1,wherein are best shown the general features of the invention, the boringtool, indicated generally by the reference numeral 10, is shown ashaving a shank 11, a cutting element 12, a suction bore 13, and meansfor effecting a suction in the suction bore, the means being indicatedgenerally by the reference numeral 14. The shank 11 is tubular in naturehaving a centrally located suction bore 13 running axially of itslength, the shank being made of material suitable for the intended useof the tool. Symmetrically mounted in notches 23 in the working end ofthe shank 11 so as not to block the bore is a tungsten carbide plateshown in FIGS. l-5. This particular cutting element is especially usefulin cast iron work due to the cutting and crushing action it bringsabout. This action renders the chips particularly easy to remove by thepresent method. The cutting element extends beyond the extremity andperiphery of the shank, thereby protecting the shank from attrition andcreating air inlet spaces as the tool functions. The cutting element issecured in the notches using a high-temperature adhesive or a weld, butthis bond does not bear the working stress. The mechanical interlockingof the element and the notches bears almost the entire burden. Thesuction is applied at the driven end of the tool.

FIG. 6 shows a section of the tool holder of FIG. 1. Involved is thedrive train 16 which includes a drive shaft 17, two bevel gears 18 and19 and a chuck 20 driven by the train and grasping the shank 11. Alsoinvolved are the driven end of the shank 11, the connection 22 to thevacuum pump 39, and the ring seal 21 between the shanks and theconnection. The ring seal allows rotation of the shank relative to theconnection while maintaining necessary air-tightness.

FIG. 7 shows a commutating coupling designated generally by the numeral40 which allows the boring tool to be used in unmodified tool holders.It involves a body 41 which grasps the working end of the shank andholds it with a set screw. A driven end of the body fits a standard toolholder. A shell 42 defines a cavity 43 outside the body and is rotatablymounted on the body. A vacuum line 44 effects a vacuum in the cavity 43.Also provided are bearings 45 and seals 46 which separate the shell andthe body, a bore 47 and ports 48 which connect the suction bore 13 ofthe shank 11 to the cavity 43, and lastly a support 49 which secures thevacuum line 44 and thereby keeps the shell 42 from rotating with theholder 40.

FIG. 8 shows the connector 50 as it joins the vacuum line 44 and thesupport 49. The connector is simply two cylinders welded at a rightangle to one another and fitted with set screws to secure the memberswhich are to be held.

FIG. 9 shows the seals 46 and bearings 45 that connect the holder 41 andthe shell 42, thereby defining the cavity 43. As shown in FIG. 7 andFIG. 9, the shell and seals may be of one piece molded construction withsnap-in bearings. The unit is then installed on the holder by sliding itover the driven end of the holder down to stops 51 and retaining it inposition with retaining ring 52.

The use and operation of the invention will now be readily understood inview of the above description. The boring tool is placed in a suitablemachine tool such as a drill press and the workpiece is positioned.Suction is applied to the suction bore 13 by a shop vacuum cleaner 39through the tool holder in the first instance and through thecommutating holder in the second instance. This suction causes a flow ofair in to the suction bore adjacent the cutting element, up the shankand through the apparatus to the shop vacuum cleaner 39. This flow ofair will carry with it any particles present at the working end of theshank. The tool is then rotated and lowered into the workpiece. Thecutting element cuts into the workpiece producing chips which continueto be crushed by the cutting element until they are small enough to bepulled up the suction bore by the flow of air. As the tool moves intothe workpiece, the flow of inlet air continues down the inlet air spaces15 that are formed by the edges of the cutting element that extendbehond the periphery of the shank. Thus, the continuous flow of airremoves the chips and, furthermore, dissipates heat formed at thecutting face. The chips move through the vacuum system and are collectedin the vacuum cleaner.

It IS ObVlOUS that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent I claim:

1. A boring tool, comprising:

a. a long shank with a hollow bore passing longitudinally through itscentral portion, said shank having a first end which is acceptable to atool holder of a machine tool, and a second end at which the bore formsan opening, said opening having a peripheral edge,

b. two notches provided in the edge, each notch having a first edgeportion associated with it on one side and a second edge portionassociated with it on the other, said first edge portion extendingaxially, substantially beyond said second edge portion, and

c. a cutting element, carried in the notches.

2. A boring tool, as recited in claim 1, wherein the said first edgeportions associated with the notches are diametrically opposed to oneanother.

3. A boring tool as recited in claim 1, wherein said bore is sealed atsaid first end.

4. A boring tool as recited in claim 1, wherein said cutting element isa plate of carbide.

5. A boring tool as recited in claim 1, wherein said cutting element ispositioned symmetrically on said shank.

6. A boring tool as recited in claim 1, wherein said means to applysuction comprises a vacuum pump and a coupling between said shank andsaid vacuum pump, so that suction is applied to said bore while saidshank is rotating.

1. A boring tool, comprising: a. a long shank with a hollow bore passinglongitudinally through its central portion, said shank having a firstend which is acceptable to a tool holder of a machine tool, and a secondend at which the bore forms an opening, said opening having a peripheraledge, b. two notches provided in the edge, each notch having a firstedge portion associated with it on one side and a second edge portionassociated with it on the other, said first edge portion extendingaxially, substantially beyond said second edge portion, and c. a cuttingelement, carried in the notches.
 2. A boring tool, as recited in claim1, wherein the said first edge portions associated with the notches arediametrically opposed to one another.
 3. A boring tool as recited inclaim 1, wherein said bore is sealed at said first end.
 4. A boring toolas recited in claim 1, wherein said cutting element is a plate ofcarbide.
 5. A boring tool as recited in claim 1, wherein said cuttingelement is positioned symmetrically on said shank.
 6. A boring tool asrecited in claim 1, wherein said means to apply suction comprises avacuum pump and a coupling between said shank and said vacuum pump, sothat suction is applied to said bore while said shank is rotating.